Transport for London Press Images:
Low Level Cycle Signal, 2018 - Copyright TfL
Transport for London Press Images:
Traffic light, Acton, 1967 - Copyright London Transport Museum
Transport for London Press Images:
Traffic light, circa 1952 - Copyright London Transport Museum
Transport for London Press Images:
Traffic light, Trafalgar Square, 1934 - Copyright London Transport Museum
Transport for London Press Images:
Traffic light, Trafalgar Square, 1936 - Copyright London Transport Museum